We run a mailing list at
http://mailman.ICSI.Berkeley.EDU/mailman/listinfo/netalyzr.
To contact us privately, please send email to netalyzr-help@icsi.berkeley.edu.
If you have a question about a particular session, please include
the session ID. It is shown in the status bar during the analysis,
and stated explicitly as the session's permalink at the top of the
summary page. You can also just cut-and-paste the URL shown by your
browser for the summary page.

What information do you collect?

We collect effectively the same information we present
to you in the summary page, and nothing else. All of this
information is collected from network connections the applet
initiates itself.

There is no launch link on the start page. Why?

Your system needs to provide a Java Runtime
Environment (JRE) for applets to operate in. Please ensure that
a JRE is installed on your machine, and that Java is enabled in
your browser. You can test your installation by visiting Sun's
Java
detector.

Why Java?

We are unable to perform all of the tests we provide
using more lightweight alternatives, such as JavaScript. In
particular, JavaScript does not enable the browser to create
arbitrary network connections.

How do I install Java?

First make sure your browser is willing to use Java and then reload the front page:
In Internet Explorer 7, go to Tools
Internet Options
Programs Manage add-ons and ensure
that the Java plugins are enabled.
In Firefox, make sure the "Enable Java" tick box under
Preferences Content is selected.
In Safari, make sure the "Enable Java" tick box under
Preferences Security is selected.
If that still doesn't work, follow the instructions at
at http://www.java.com/getjava/ to download and install Java.

Why JavaScript?

Some information, such as cookies or framing, can't be
detected within Java but can be detected by JavaScript. Thus in
addition to the Java applet, there is a small amount of JavaScript on
our analysis page to perform these checks.

Are you accessing any information on my computer?

We do not touch any files on your disk. The only system-local
information we use is your local time, what IP address Java
believes has been assigned to your machine, and what information
your browser routinely exposes (its "user agent" and cookies
it automatically provides because you have visited our sites
before). All other information is obtained from the network.

Are you probing my local network?

Almost all network connectivity is exclusively with
your DNS resolver, our servers, and any proxies in front of them.
There are only two exceptions. The first is that, if the user is
behind a NAT, Netalyzr attempts to check if the NAT is operating a
DNS proxy or resolver and, if so, checks that this proxy is
operating correctly. The second is a test for Universal Plug and
Play (UPnP) support, a protocol used to talk to NATs, media
players, and other devices in the home. Netalyzr uses UPnP to ask
"Are there any NATs?" and, if any NAT replies, "What sort of NAT
are you?".

The results state the applet was not permitted to
conduct all tests. How can I allow the tests?

The applet operates within the confines of the
security policy enforced by your Java runtime. When the applet
attempts to perform an operation that violates this policy, a
security exception is thrown, and the operation is not
executed. Browsers handle these security restrictions in a variety
of ways. By confirming that you trust the applet, many browsers
will allow the applet to conduct all tests. However, some Java
installations will not allow certain tests to run, even if the user
gives consent. If you are asked to confirm individual operations,
we suggest to permit them as required to complete the tests.

My anti-virus program triggered an alert while Netalyzr was running.
Why?

As part of our content-filtering tests, we download the EICAR
antivirus test file into the applet. This file is harmless and
designed to test correct functionality of antivirus software. Any
related warnings or alerts thus merely signal correct functioning of
your antivirus installation and can safely be ignored.

Netalyzr reports large buffers in my up/downlink. How can I fix that?

The first option is just to be aware of the issue. If you don't try
to perform large file transfers or P2P applications while also
websurfing, gaming, or using VoIP, you shouldn't notice a problem.
Buffer sizing is only a problem if you try to perform both large
transfers and interactive applications simultaneously.
The second is to pay for a higher bandwidth service, if it is
important for you to be able to perform both large file transfers and
interactive applications at the same time. The problem is due to the
ratio between the buffer's capacity and the bandwidth of the
connection, so if you pay for more bandwidth, the buffering problem is
reduced.
Unfortunately the real solution, namely access devices which allow
programmable buffer sizing or dynamically resize their buffer based on
available bandwidth, is not generally available to the customer at
this time.

Who developed Netalyzr?

Netalyzr is developed by the Networking Group at
the International Computer
Science Institute, an independent non-profit research institute
affiliated with the University of California, Berkeley, USA.

Our Netalyzr is unrelated to any of Safer Networking's products.
However, Safer Networking holds a trademark on the name
NetAlyzer.
We chose the name for our tool before we had learned of this conflict.
Safer Networking has graciously agreed to allow us to continue using
the name.

Who funded this work?

This work is sponsored by the National Science
Foundation, the Department of Homeland Security Science and Technology
Directorate's Cyber Security Division, and by generous gifts from
Amazon, Comcast, and Google.
Heise Netze for funding the
translation services for the site's German version.